Vegetation and
Environmental
New
Micro
Spacecraft
(VENmS)
Recent initiative of the Israeli
Space Agency (ISA) and the French space agency (CNES) is aimed at developing, manufacturing, and
operating a new Earth observing satellite called ‘Vegetation and
Environment monitoring New Micro-Satellite’ (VENµS). The satellite
is planned to be launched in early 2009, and the scientific mission
should last at least two years.
The general mission objectives are the provision of data for
scientific studies dealing with the monitoring, analysis, and
modeling of land surface functioning under the influences of
environmental factors as well as human activities. The VENµS
scientific mission is also aimed at demonstrating the relevance of
superspectral, high spatial resolution observations combined with
frequent revisit capabilities in the framework of the European
Global Monitoring for Environment and Security Program (the "GMES
Program").
In
order to implement these goals, the mission will acquire frequent,
high resolution, multi-spectral images of sites of interest all
around the world. The satellite will fly in a near polar
sun-synchronous orbit at 720 km height. The whole system will be
able to be tilted up to 30 degree along and across track. This
configuration will result in a 2-days revisit time, 27 km swath, a
camera resolution of 5.3 m, and the capability to observe any site
under a constant view angle. The system will cross the equator at
around 10:30 AM.
The satellite will carry a super-spectral camera characterized by 12
narrow spectral bands ranging from 415 to 910 nm. The band setting
was designed to characterize vegetation status, including through
red-edge bands, and to estimate the aerosol optical depth and the
water vapour content of the atmosphere for accurate atmospheric
corrections. The spectral band setting could also prove useful for
coastal areas and inland waters studies. The satellite will also
carry a Technological Payload – the Israeli Hall Effect Thruster (IHET)
– to validate its performance and for orbit keeping.
The data will be acquired over existing or planned experimental
sites with size ranging from a few kilometers to 27 x 100 km or
more. All data for a given site will be acquired with the same
observation angle in order to minimize directional effects. The
baseline product for these selected sites is time composite images
of geometrically registered surface reflectances at 10 m resolution.
Strong efforts are devoted to provide high quality data, both in
term of radiometry (e.g. SNR around 100), geometry (e.g.
multitemporal registration better than 3 m), and atmospheric
corrections. |